ACPAtmospheric Chemistry and PhysicsACPAtmos. Chem. Phys.1680-7324Copernicus GmbHGöttingen, Germany10.5194/acp-8-3325-2008Detection of regional scale sea-to-air oxygen emission related to spring bloom near Japan by using in-situ measurements of the atmospheric oxygen/nitrogen ratioYamagishiH.1TohjimaY.1MukaiH.2SasaokaK.31Atmospheric Environment Division, National Institute for Environmental Studies, Tsukuba, Japan2Center for Global Environmental Research, National Institute for Environmental Studies, Tsukuba, Japan3Frontier Research Center for Global Change, Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan2706200881233253335This work is licensed under a Creative Commons Attribution 3.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by/3.0/This article is available from http://www.atmos-chem-phys.net/8/3325/2008/acp-8-3325-2008.htmlThe full text article is available as a PDF file from http://www.atmos-chem-phys.net/8/3325/2008/acp-8-3325-2008.pdf

We have been carrying out in-situ monitoring of atmospheric O<sub>2</sub>/N<sub>2</sub>
ratio at Cape Ochi-ishi (COI; 43&deg;10' N, 145&deg;30' E) in the northern
part of Japan since March 2005 by using a modified gas
chromatography/thermal conductivity detector (GC/TCD). The standard
deviation of the O<sub>2</sub>/N<sub>2</sub> ratio is estimated to be about &plusmn;14 per
meg (&asymp;3 ppm) with intervals of 10 minutes. Thus, the in-situ
measurement system has a 1σ precision of &plusmn; 6 per meg (&asymp;1.2 ppm)
for one-hour mean O<sub>2</sub>/N<sub>2</sub> ratio. Atmospheric potential
oxygen (APO&asymp;O<sub>2</sub>+1.1 CO<sub>2</sub>), which is conserved with
respect to terrestrial photosynthesis and respiration but reflects changes
in air-sea O<sub>2</sub> and CO<sub>2</sub> fluxes, shows large variabilities from April
to early July 2005. Distribution of satellite-derived marine primary
production indicates occurrences of strong bloom in the Japan Sea and the
latitudinal band between 30&deg; and 40&deg; N in the western North Pacific
in April and in the Okhotsk Sea and northeastern region near Hokkaido Island
in the North Pacific in June. Back trajectory analysis of air masses
indicates that high values of APO, which last for several hours or several
days, can be attributed to the oxygen emission associated with the spring
bloom of active primary production.